Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ISOVUE-128 vs ISOVUE-370
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Isovue-128 (iopamidol) is a nonionic, water-soluble, radiographic contrast medium that enhances imaging by attenuating X-rays, thereby increasing contrast between vascular structures and surrounding tissues. Its mechanism is based on the high iodine content which absorbs X-rays, allowing visualization of blood vessels and organs during angiography, urography, and CT scans.
Iodinated contrast agent that attenuates X-rays, providing radiographic contrast by increasing the density of vascular structures and tissues.
Intravascular use for computed tomography (CT) imaging,Intravenous urography,Intra-arterial angiography (including coronary, peripheral, and cerebral),Ventriculography,Myelography (subarachnoid injection for spinal imaging),Off-label: Arthrography, hysterosalpingography (though not FDA-approved for these)
Intravascular administration for computed tomography (CT) imaging,Intrathecal administration for myelography (CT and conventional),Angiography (coronary, cerebral, peripheral, etc.),Intravenous urography,Left ventriculography,Arteriography,Other radiographic contrast procedures
Adult: 50-200 m L (0.5-2.0 m L/kg) intravenously, single dose for contrast-enhanced CT; for angiography, dose and rate vary by procedure.
Intravenous injection of 50-200 m L of Isovue-370 (iopamidol 76% solution, 370 mg I/m L) for adults, administered as a bolus or infusion depending on imaging protocol. Typical dose for CT: 100-150 m L total volume.
Terminal elimination half-life is approximately 1.5-2 hours in patients with normal renal function; prolonged in renal impairment (up to 8-10 hours with GFR <30 m L/min).
Terminal elimination half-life is approximately 1.5-2 hours in patients with normal renal function (creatinine clearance >60 m L/min); prolonged to up to 30 hours in severe renal impairment.
Iopamidol is not metabolized and is excreted unchanged almost entirely by the kidneys via glomerular filtration. No hepatic metabolism or significant protein binding occurs.
Not metabolized; eliminated unchanged via glomerular filtration.
Renal: >95% excreted unchanged in urine via glomerular filtration; fecal/biliary: <5%.
Primarily renal (glomerular filtration) with >95% of administered dose excreted unchanged in urine within 24 hours. Less than 1% excreted in feces.
Minimal protein binding (<5%), primarily to albumin.
Minimal; approximately 1-5% bound to serum proteins (primarily albumin).
Approximately 0.2-0.3 L/kg, reflecting distribution into extracellular fluid.
Volume of distribution (Vd) is approximately 0.2-0.3 L/kg, reflecting distribution primarily in extracellular fluid (plasma and interstitial space).
Not applicable for oral route (no oral formulation); 100% bioavailability via intravenous or intra-arterial administration.
Not applicable (administered intravascularly); bioavailability is 100% for intravenous and intra-arterial routes as it does not undergo first-pass metabolism.
GFR <30 m L/min: use lowest feasible dose; GFR <15 m L/min: avoid use unless essential; consider hydration and N-acetylcysteine.
No specific dose adjustment guidelines exist for Isovue-370 in renal impairment; however, caution is advised. In patients with GFR < 30 m L/min/1.73m², use lowest necessary dose and ensure adequate hydration. Hemodialysis may remove contrast; post-procedure dialysis can be considered.
No specific Child-Pugh based adjustments; use with caution in severe hepatic impairment due to risk of contrast-induced nephropathy.
No specific dose adjustment is required based on hepatic impairment; monitor renal function closely in patients with severe hepatic disease due to potential reduced clearance.
Neonates: 0.5-1 m L/kg IV; Infants/Children: 1-2 m L/kg IV (max 125 m L per dose) for contrast-enhanced CT.
Weight-based dosing: 1-2 m L/kg (3.7-7.4 mg I/kg) intravenously, not exceeding 3 m L/kg total dose. Adjusted based on imaging indication and patient factors; for CT, 1.5-2 m L/kg typical.
Reduce dose to lowest effective (e.g., 50-100 m L); ensure adequate hydration; monitor renal function pre and post administration.
Elderly patients may require lower doses due to age-related renal impairment and increased risk of contrast-induced nephropathy. Use the minimal effective dose and ensure adequate hydration. Individualize based on renal function.
Iodinated contrast media including iopamidol are associated with an increased risk of contrast-induced acute kidney injury (CI-AKI) in patients with pre-existing renal impairment, particularly those with diabetes, volume depletion, or concurrent use of nephrotoxic drugs. Strict adherence to hydration protocols and renal monitoring is required.
No FDA black box warning.
Risk of contrast-induced nephropathy (CIN): Monitor renal function before and after administration, ensure adequate hydration, and avoid concurrent nephrotoxic agents.,Severe hypersensitivity reactions (e.g., anaphylaxis, bronchospasm): Have resuscitation equipment available; premedication may be considered for patients with known contrast allergy.,Thyroid dysfunction: Iodinated contrast may induce hyperthyroidism or hypothyroidism; caution in patients with thyroid disease.,Cardiovascular events: In patients with heart failure, coronary artery disease, or pulmonary hypertension, contrast media can cause hemodynamic instability, arrhythmias, or myocardial ischemia.,Neurologic effects: Intrathecal administration may cause seizures, arachnoiditis, or aseptic meningitis; use lowest possible dose and monitor for neurotoxicity.,Extravasation: Risk of tissue necrosis; administer through a secure IV line and monitor injection site.
Risk of serious anaphylactic reactions; have emergency equipment available.,Acute renal toxicity, especially in patients with pre-existing renal impairment, diabetes, or dehydration.,Contrast-induced nephropathy; ensure adequate hydration.,Extravasation risk; monitor injection site.,Thyroid storm in patients with hyperthyroidism or thyroid nodules.,Severe cutaneous adverse reactions (e.g., Stevens-Johnson syndrome).,Exacerbation of sickle cell disease.,Intrathecal use may cause neurotoxicity; avoid high doses.
Absolute: Known hypersensitivity to iopamidol, other iodine-containing contrast media, or any component of the formulation.,Absolute: Intrathecal administration in patients with significant thrombophlebitis or infection at the injection site.,Relative: Pre-existing renal impairment (e GFR <30 m L/min/1.73m²) unless benefits outweigh risks; consider alternative imaging.,Relative: Multiple myeloma, pheochromocytoma, sickle cell disease (due to risk of vaso-occlusive events).,Relative: Pregnancy (especially first trimester) unless essential for diagnosis.
History of hypersensitivity to iopamidol or other iodinated contrast agents.,Acute pancreatitis (for intrathecal use).,Intrathecal administration in patients with blood in CSF or increased intracranial pressure.,Anuria or severe renal impairment (relative).
No specific food interactions. However, patients are often advised to maintain adequate hydration. Avoid alcohol consumption for 24 hours before and after the procedure as it may increase risk of dehydration. No dietary restrictions required.
No specific food restrictions are required for this contrast agent. Maintain adequate hydration before and after administration. No known food-drug interactions.
Iodinated contrast agents, including iopamidol (ISOVUE-128), are generally considered low risk for teratogenicity in humans based on limited data. In the first trimester, there is a theoretical risk of fetal hypothyroidism due to free iodide, but clinical evidence does not show a significant increase in congenital anomalies. Second and third trimester exposure is associated with transient neonatal hypothyroidism if the agent crosses the placenta, but no structural teratogenic effects are documented. The FDA assigns a Pregnancy Category B for iodinated contrast agents.
Iodinated contrast media, including iopamidol (ISOVUE-370), cross the placenta. In animal studies, no teratogenic effects were observed at clinically relevant doses. However, due to potential fetal hypothyroidism from free iodide exposure, use in pregnancy only if clearly needed. First trimester: theoretical risk of fetal thyroid suppression; second and third trimesters: risk of neonatal hypothyroidism if high doses or repeated exposures. No documented congenital malformations in human data.
Iopamidol is excreted into breast milk in very small amounts. The milk-to-plasma (M/P) ratio is approximately 0.04–0.08 based on limited studies. The absolute dose received by a nursing infant is estimated to be less than 0.01% of the maternal dose, which is clinically insignificant. Therefore, breastfeeding can be continued without interruption, although some experts suggest discarding milk for 24 hours post-administration as a precaution. No adverse effects on the infant have been reported.
Iopamidol is excreted into human breast milk in minimal amounts (estimated infant dose <0.01% of maternal dose). M/P ratio not available. Because of low oral bioavailability and rapid milk clearance, breastfeeding can be continued without interruption; some sources suggest discarding milk for 12-24 hours post-procedure as a precaution.
No dosing adjustments are required for iopamidol (ISOVUE-128) during pregnancy based on pharmacokinetic changes. However, because physiological changes in pregnancy (increased plasma volume, increased renal clearance) may affect contrast agent distribution and elimination, the standard dose should be used based on body weight and indication. The lowest effective dose should be administered to minimize fetal exposure. No specific dose modifications are recommended in guidelines.
No specific dose adjustment required for pregnancy based on pharmacokinetic changes. However, because of increased plasma volume and glomerular filtration rate in pregnancy, the elimination half-life may be slightly reduced. Use the lowest effective dose to minimize fetal iodide exposure. Adequate hydration is essential to prevent contrast-induced nephropathy.
ISOVUE-128 (iopamidol) is a nonionic, low-osmolality contrast medium. Pre-warming to body temperature reduces viscosity and improves patient tolerance. Risk of contrast-induced nephropathy (CIN) increases with pre-existing renal impairment; assess renal function (e GFR) prior to administration. Adequate hydration is critical. Monitor for delayed hypersensitivity reactions (up to 7 days). Metformin should be withheld for 48 hours post procedure if renal function is compromised. Have emergency equipment available for anaphylactoid reactions.
Pre-warm contrast to body temperature to reduce viscosity and patient discomfort. Assess renal function (e GFR >30 m L/min/1.73m²) prior to administration; use lowest possible dose in patients with renal impairment. Have emergency equipment available for hypersensitivity reactions. For intravascular use, ensure adequate hydration before and after procedure. In diabetic patients taking metformin, withhold metformin for 48 hours post-contrast and monitor renal function.
Inform your healthcare provider if you have any allergies, especially to contrast media or iodine.,Tell your provider about all medications you take, particularly metformin or any kidney-affecting drugs.,You may be asked to drink extra fluids before and after the procedure to protect your kidneys.,Report any symptoms like hives, itching, difficulty breathing, or swelling of the face/throat immediately.,If you have diabetes and take metformin, your doctor may advise stopping it for 48 hours after the scan.,Sensation of warmth, a metallic taste, or nausea during injection is common and usually resolves quickly.,After the procedure, you can resume normal diet unless directed otherwise.
Inform your doctor if you have a history of allergic reactions to contrast media, asthma, or allergies.,Drink plenty of fluids before and after the procedure to help protect your kidneys.,Report any symptoms such as hives, itching, difficulty breathing, or swelling of the face/throat immediately.,If you are diabetic and take metformin, ask your doctor about temporarily stopping it.,You may feel warmth or a metallic taste during injection; these sensations are temporary.,Notify your doctor if you are pregnant, nursing, or have kidney disease.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ISOVUE-128 vs ISOVUE-370, answered by our medical review team.
ISOVUE-128 is a Contrast Media that works by Isovue-128 (iopamidol) is a nonionic, water-soluble, radiographic contrast medium that enhances imaging by attenuating X-rays, thereby increasing contrast between vascular structures and surrounding tissues. Its mechanism is based on the high iodine content which absorbs X-rays, allowing visualization of blood vessels and organs during angiography, urography, and CT scans.. ISOVUE-370 is a Contrast Media that works by Iodinated contrast agent that attenuates X-rays, providing radiographic contrast by increasing the density of vascular structures and tissues.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ISOVUE-128 and ISOVUE-370 depend on the specific clinical indication. These are both Contrast Media agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ISOVUE-128 is: Adult: 50-200 m L (0.5-2.0 m L/kg) intravenously, single dose for contrast-enhanced CT; for angiography, dose and rate vary by procedure.. The standard adult dose of ISOVUE-370 is: Intravenous injection of 50-200 m L of Isovue-370 (iopamidol 76% solution, 370 mg I/m L) for adults, administered as a bolus or infusion depending on imaging protocol. Typical dose for CT: 100-150 m L total volume.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ISOVUE-128 and ISOVUE-370 in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ISOVUE-128 is classified as Category C. Iodinated contrast agents, including iopamidol (ISOVUE-128), are generally considered low risk for teratogenicity in humans based on limited data. In the first trimester, there is . ISOVUE-370 is classified as Category C. Iodinated contrast media, including iopamidol (ISOVUE-370), cross the placenta. In animal studies, no teratogenic effects were observed at clinically relevant doses. However, due t. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.